Computer graphical user interfaces are typically rendered using a physical Graphical Processing Unit (GPU), and then displayed on a monitor connected to the GPU via standard physical graphics interface cables such as DVI, VGA, DisplayPort, or HDMI. This typical configuration has certain limitations when attempting to create systems with larger numbers of monitors. For instance, typical personal computers (PCs) come with only one or two monitor ports. After-market graphics cards with more than two ports can be purchased for desktop PCs, but these cards are relatively expensive. Typical desktop PC motherboards have only one or two expansion slots for graphics cards, and configurations with more expansion slots require custom PCs which are expensive and complicated to assemble and maintain. Also, standard physical graphics cables have limited distances across which they will function.
Various technologies have been developed that allow users to connect monitors to computers over different interfaces, such as USB. These technologies generally involve manipulation of the video driver stack in order to present more monitors to the OS than are actually physically connected to the GPU. Such technologies can introduce poor reliability due to video filter drivers that are difficult to develop and highly susceptible to breaks resulting from changes in the GPU's driver.